cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-4 of 4 results.

A133233 Triangle A133232 read by rows with an additional column T(n,0)=1 added to the left.

Original entry on oeis.org

1, 1, 1, 1, 1, 2, 1, 1, 2, 3, 1, 1, 1, 3, 4, 1, 1, 1, 3, 4, 5, 1, 1, 1, 3, 4, 5, 1, 1, 1, 1, 3, 4, 5, 1, 7, 1, 1, 1, 3, 1, 5, 1, 7, 8, 1, 1, 1, 1, 1, 5, 1, 7, 8, 9, 1, 1, 1, 1, 1, 5, 1, 7, 8, 9, 1, 1, 1, 1, 1, 1, 5, 1, 7, 8, 9, 1, 11, 1, 1, 1, 1, 1, 5, 1, 7, 8, 9, 1, 11, 1, 1, 1, 1, 1, 1, 5, 1, 7, 8, 9, 1, 11
Offset: 0

Views

Author

Mats Granvik, Oct 13 2007

Keywords

Comments

Attaching an additional 1 does not change the composition compared to A133232 since neither the LCM over the elements of a row nor their product is affected.

Examples

			The first rows of the triangle and the least common multiple of the rows are:
lcm{1} = 1
lcm{1, 1} = 1
lcm{1, 1, 2} = 2
lcm{1, 1, 2, 3} = 6
lcm{1, 1, 1, 3, 4} = 12
lcm{1, 1, 1, 3, 4, 5} = 60
lcm{1, 1, 1, 3, 4, 5, 1} = 60
lcm{1, 1, 1, 3, 4, 5, 1, 7} = 420
lcm{1, 1, 1, 3, 1, 5, 1, 7, 8} = 840
lcm{1, 1, 1, 1, 1, 5, 1, 7, 8, 9} = 2520
Multiplying the terms in the rows produces the same result:
1 = 1
1*1 = 1
1*1*2 = 2
1*1*2*3 = 6
1*1*1*3*4 = 12
1*1*1*3*4*5 = 60
1*1*1*3*4*5*1 = 60
1*1*1*3*4*5*1*7 = 420
1*1*1*3*1*5*1*7*8 = 840
1*1*1*1*1*5*1*7*8*9 = 2520
		

Crossrefs

Formula

T(n,0) = 1.
T(n,k) = A133232(n,k), k>0.

Extensions

Removed information which duplicates A133232; offset set to 0 - R. J. Mathar, Nov 23 2010

A133232 Triangle T(n,k) read by rows with a minimum number of prime powers A100994 for which the least common multiple of T(n,1),..,T(n,n) is A003418(n).

Original entry on oeis.org

1, 1, 2, 1, 2, 3, 1, 1, 3, 4, 1, 1, 3, 4, 5, 1, 1, 3, 4, 5, 1, 1, 1, 3, 4, 5, 1, 7, 1, 1, 3, 1, 5, 1, 7, 8, 1, 1, 1, 1, 5, 1, 7, 8, 9, 1, 1, 1, 1, 5, 1, 7, 8, 9, 1, 1, 1, 1, 1, 5, 1, 7, 8, 9, 1, 11, 1, 1, 1, 1, 5, 1, 7, 8, 9, 1, 11, 1, 1, 1, 1, 1, 5, 1, 7, 8, 9, 1, 11, 1, 13, 1, 1, 1, 1, 5, 1, 7, 8, 9, 1, 11, 1
Offset: 1

Views

Author

Mats Granvik, Oct 13 2007

Keywords

Comments

Checked up to 28th row. The rest of the ones in the table are there for the least common multiple to calculate correctly.

Examples

			2 occurs 2*1 = 2 times in column 2.
3 occurs 3*2 = 6 times in column 3.
4 occurs 4*1 = 4 times in column 4.
5 occurs 5*4 = 20 times in column 5.
k occurs A133936(k) times in column k. The first rows of the triangle and the least common multiple of the rows are:
lcm{1} = 1
lcm{1, 2} = 2
lcm{1, 2, 3} = 6
lcm{1, 1, 3, 4} = 12
lcm{1, 1, 3, 4, 5} = 60
lcm{1, 1, 3, 4, 5, 1} = 60
lcm{1, 1, 3, 4, 5, 1, 7} = 420
lcm{1, 1, 3, 1, 5, 1, 7, 8} = 840
lcm{1, 1, 1, 1, 5, 1, 7, 8, 9} = 2520
		

Crossrefs

Programs

  • Excel
    =if(and(row()>=column();row()A120112));column();1)
    
  • Excel
    =if(and(n>=k; n < A014963*A100994); A100994; 1) - Mats Granvik, Jan 21 2008
  • Maple
    A120112 := proc(n) 1-ilcm(seq(i,i=1..n+1))/ilcm(seq(i,i=1..n)) ; end proc:
    A133232 := proc(n) if n < k*(1+abs(A120112(k-1))) then k else 1; end if; end proc:
    seq(seq(A133232(n,k),k=1..n),n=1..15) ; # R. J. Mathar, Nov 23 2010
  • Mathematica
    b[n_] := b[n] = If[n == 0, 1, LCM @@ Range[n]];
    c[n_] := 1 - b[n+1]/b[n];
    T[n_, k_] := If[n < k*(1+Abs[c[k-1]]), k, 1];
    Table[T[n, k], {n, 1, 10}, {k, 1, n}] // Flatten (* Jean-François Alcover, Mar 01 2021 *)

Formula

T(n,k) = if nA120112(k-1)| then k, else 1 (1<=k<=n).
T(n,k) = if n < A014963(k)*A100994(k) then A100994(k), else 1 (1<=k<=n). - Mats Granvik, Jan 21 2008

Extensions

Indices added to formulas by R. J. Mathar, Nov 23 2010

A120111 Bi-diagonal inverse matrix of A120108.

Original entry on oeis.org

1, -2, 1, 0, -3, 1, 0, 0, -2, 1, 0, 0, 0, -5, 1, 0, 0, 0, 0, -1, 1, 0, 0, 0, 0, 0, -7, 1, 0, 0, 0, 0, 0, 0, -2, 1, 0, 0, 0, 0, 0, 0, 0, -3, 1, 0, 0, 0, 0, 0, 0, 0, 0, -1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11, 1
Offset: 0

Views

Author

Paul Barry, Jun 09 2006

Keywords

Comments

Subdiagonal is -lcm(1,...,n+2)/lcm(1,...,n+1) or -A014963(n+1).
Row sums are A120112.

Examples

			Triangle begins
   1;
  -2,  1;
   0, -3,  1;
   0,  0, -2,  1;
   0,  0,  0, -5,  1;
   0,  0,  0,  0, -1,  1;
   0,  0,  0,  0,  0, -7,  1;
   0,  0,  0,  0,  0,  0, -2,  1;
   0,  0,  0,  0,  0,  0,  0, -3,  1;
   0,  0,  0,  0,  0,  0,  0,  0, -1,   1;
   0,  0,  0,  0,  0,  0,  0,  0,  0, -11, 1;
		

Crossrefs

Programs

  • Magma
    A014963:= func< n | Lcm([1..n])/Lcm([1..n-1]) >;
    A120111:= func< n,k | k eq n select 1 else k eq n-1 select -A014963(n+1) else 0 >;
    [A120111(n,k): k in [0..n], n in [0..15]]; // G. C. Greubel, May 05 2023
    
  • Mathematica
    T[n_, k_] := Switch[k, n, 1, n-1, -Exp[MangoldtLambda[n+1]], _, 0];
    Table[T[n, k], {n,0,15}, {k,0,n}]//Flatten (* Jean-François Alcover, Mar 01 2021 *)
    (* Second program *)
    A014963[n_]:= LCM@@Range[n]/(LCM@@Range[n-1]);
    A120111[n_, k_]:= If[k==n, 1, If[k==n-1, -A014963[n+1], 0]];
    Table[A120111[n,k], {n,0,20}, {k,0,n}]//Flatten (* G. C. Greubel, May 05 2023 *)
  • SageMath
    def A014963(n): return lcm(range(1,n+1))/lcm(range(1,n))
    def A120111(n,k):
        if (kA014963(n+1)
        else: return 1
    flatten([[A120111(n,k) for k in range(n+1)] for n in range(16)]) # G. C. Greubel, May 05 2023

A276048 Sequence associated with the functional equation of the Riemann zeta zero spectrum (see formulas).

Original entry on oeis.org

0, 2, 9, 2, 625, 1, 117649, 2, 9, 1, 25937424601, 1, 23298085122481, 1, 1, 2, 48661191875666868481, 1, 104127350297911241532841, 1, 1, 1, 907846434775996175406740561329, 1, 625, 1, 9, 1, 88540901833145211536614766025207452637361, 1
Offset: 1

Views

Author

Mats Granvik, Aug 17 2016

Keywords

Comments

The functional equation formula in the answer by Peter Humphries is for the Dirichlet eta function and corresponds to the second term in this sequence. This sequence corresponds to zeta function products over all the divisors.

Crossrefs

Programs

  • Mathematica
    Clear[s]; -Table[Limit[Zeta[s]*Total[MoebiusMu[Divisors[n]]*Divisors[n]^(1 - (s))]*Total[MoebiusMu[Divisors[n]]*Divisors[n]^(s)], s -> 1], {n, 1, 30}]; Exp[%]

Formula

a(n) = exp(lim_{s->1} zeta(s)*Sum_{d|n} mu(d)*d^(1 - s)*Sum_{d|n} mu(d)*d^(s)).
a(n) = A014963(n)^(A014963(n)-1), n > 1.
a(n) = A014963(n)^(-A120112(n)), n > 1.
a(prime(n)) = A000169(prime(n)).
Showing 1-4 of 4 results.